This invention relates to a patterning method using laser scribing.
Laser scribing is a now developing technique in semiconductor manufacture for substituting conventional patterning method such as photolithography, etching or the like. This technique is advantageous in that fine patterns can be produced at a minimum spacing of 10 microns by its simplified process. The applicants have filed a Japanese Patent Application No. sho 57-206807 concerning this technique, in which is described a manufacturing process for non-single crystalline silicon semiconductor solar cell. According to this prior art invention, semiconductor materials are laminated on a glass substrate, and then the laminate members are severed by laser scribing to produced an integrated structure.
However, when the semiconductor layer is irradiated with a laser beam, protrusions 7 are formed at the both sides of a groove engraved as illustrated in FIG. 2. The spacial energy distribution of laser beam across its width is shown in FIG. 1. Side tail 6 of the distribution is the cause of the formation of the protrusion. The height of the protrusion is generally between 50% and 100% of the thickness of the layer to be processed. The protrusion tends to form adverse circuitry which interconnects the constituent layers of the laminated semiconductor and yield fissures on a film ovelying the protrusion.
There are several attempt for handling the prior art problem, such as the elimination of the protrusion by wet or dry etching. However, no effective measure has been proposed yet. Because of this, at this present, laser scribing is only applicable to semiconductor devices which are less affected by the formation of the protrusions, or the patterning of thin films such as solar cell manufacture.